1,652 research outputs found
A star-forming galaxy at z= 5.78 in the Chandra Deep Field South
We report the discovery of a luminous z = 5.78 star-forming galaxy in the Chandra Deep Field South. This galaxy was selected as an âi-dropâ from the GOODS public survey imaging with the Hubble Space Telescope/Advanced Camera for Surveys (object 3 in the work of Stanway, Bunker & McMahon 2003). The large colour of (iâČâzâČ)AB = 1.6 indicated a spectral break consistent with the Lyman α forest absorption shortward of Lyman α at zâ 6. The galaxy is very compact (marginally resolved with ACS with a half-light radius of 0.08 arcsec, so rhl 5. Our spectroscopic redshift for this object confirms the validity of the iâČ-drop technique of Stanway et al. to select star-forming galaxies atzâ 6
Construction and measurements of a vacuum-swing-adsorption radon-mitigation system
Long-lived alpha and beta emitters in the Rn decay chain on (and
near) detector surfaces may be the limiting background in many experiments
attempting to detect dark matter or neutrinoless double-beta decay, and in
screening detectors. In order to reduce backgrounds from radon-daughter
plate-out onto the wires of the BetaCage during its assembly, an
ultra-low-radon cleanroom is being commissioned at Syracuse University using a
vacuum-swing-adsorption radon-mitigation system. The radon filter shows
~20 reduction at its output, from 7.470.56 to 0.370.12
Bq/m, and the cleanroom radon activity meets project requirements, with a
lowest achieved value consistent with that of the filter, and levels
consistently < 2 Bq/m.Comment: 5 pages, 3 figures, Proceedings of Low Radioactivity Techniques (LRT)
2013, Gran Sasso, Italy, April 10-12, 201
Integrating Learning And Visualization Technologies In Orthopaedics:- Establishing The Virtual Orthopaedic European University
Digital technologies offer a working environment for familiarisation with new surgical procedures and management of clinical case audit. Our aim is to provide a novel route for access to educational material that more closely resembles the working practice of the arthroscopist. This is to support higher surgical training and life long learning. The proof of concept has been the development of a shoulder arthroscopy simulation model as an interface for the surgical trainee to access multimedia based educational orthopaedic modules. This demonstrates a human-computer interface that more closely resembles the process of factual knowledge association during clinical procedures, moving toward the ultimate goal of seamless integration of knowledge repositories with clinical intervention operative video information, integrating the structured surgical course model with the multimedia educational orthopaedic modules, generated for the learning of shoulder surgery
Collisional Semiclassical Aproximations in Phase-Space Representation
The Gaussian Wave-Packet phase-space representation is used to show that the
expansion in powers of of the quantum Liouville propagator leads, in
the zeroth order term, to results close to those obtained in the statistical
quasiclassical method of Lee and Scully in the Weyl-Wigner picture. It is also
verified that propagating the Wigner distribution along the classical
trajectories the amount of error is less than that coming from propagating the
Gaussian distribution along classical trajectories.Comment: 20 pages, REVTEX, no figures, 3 tables include
Nonstatistical dynamics on potentials exhibiting reaction path bifurcations and valley-ridge inflection points
We study reaction dynamics on a model potential energy surface exhibiting
post-transition state bifurcation in the vicinity of a valley ridge inflection
point. We compute fractional yields of products reached after the VRI region is
traversed, both with and without dissipation. It is found that apparently minor
variations in the potential lead to significant changes in the reaction
dynamics. Moreover, when dissipative effects are incorporated, the product
ratio depends in a complicated and highly non-monotonic fashion on the
dissipation parameter. Dynamics in the vicinity of the VRI point itself play
essentially no role in determining the product ratio, except in the highly
dissipative regime.Comment: 33 pages, 10 figures, corrected the author name in reference [6
A star-forming galaxy at z = 5.78 in the Chandra Deep Field South
We report the discovery of a luminous z = 5.78 star-forming galaxy in the Chandra Deep Field South. This galaxy was selected as an âi-dropâ from the GOODS public survey imaging with the Hubble Space Telescope/Advanced Camera for Surveys (object 3 in the work of Stanway, Bunker & McMahon 2003). The large colour of (iâČâzâČ)áŽÊ = 1.6 indicated a spectral break consistent with the Lyman α forest absorption shortward of Lyman α at zâ 6. The galaxy is very compact (marginally resolved with ACS with a half-light radius of 0.08 arcsec, so rââ 5. Our spectroscopic redshift for this object confirms the validity of the iâČ-drop technique of Stanway et al. to select star-forming galaxies at z â 6
Using Bars As Signposts of Galaxy Evolution at High and Low Redshifts
An analysis of the NICMOS Deep Field shows that there is no evidence of a
decline in the bar fraction beyond z~0.7, as previously claimed; both
bandshifting and spatial resolution must be taken into account when evaluating
the evolution of the bar fraction. Two main caveats of this study were a lack
of a proper comparison sample at low redshifts and a larger number of galaxies
at high redshifts. We address these caveats using two new studies. For a proper
local sample, we have analyzed 134 spirals in the near-infrared using 2MASS
(main results presented by Menendez-Delmestre in this volume) which serves as
an ideal anchor for the low-redshift Universe. In addition to measuring the
mean bar properties, we find that bar size is correlated with galaxy size and
brightness, but the bar ellipticity is not correlated with these galaxy
properties. The bar length is not correlated with the bar ellipticity. For
larger high redshift samples we analyze the bar fraction from the 2-square
degree COSMOS ACS survey. We find that the bar fraction at z~0.7 is ~50%,
consistent with our earlier finding of no decline in bar fraction at high
redshifts.Comment: In the proceedings of "Penetrating Bars through Masks of Cosmic Dust:
The Hubble Tuning Fork strikes a New Note
State-to-State Differential and Relative Integral Cross Sections for Rotationally Inelastic Scattering of H2O by Hydrogen
State-to-state differential cross sections (DCSs) for rotationally inelastic
scattering of H2O by H2 have been measured at 71.2 meV (574 cm-1) and 44.8 meV
(361 cm-1) collision energy using crossed molecular beams combined with
velocity map imaging. A molecular beam containing variable compositions of the
(J = 0, 1, 2) rotational states of hydrogen collides with a molecular beam of
argon seeded with water vapor that is cooled by supersonic expansion to its
lowest para or ortho rotational levels (JKaKc= 000 and 101, respectively).
Angular speed distributions of fully specified rotationally excited final
states are obtained using velocity map imaging. Relative integral cross
sections are obtained by integrating the DCSs taken with the same experimental
conditions. Experimental state-specific DCSs are compared with predictions from
fully quantum scattering calculations on the most complete H2O-H2 potential
energy surface. Comparison of relative total cross sections and state-specific
DCSs show excellent agreement with theory in almost all detailsComment: 46 page
- âŠ